The influence of fetal genotype upon endometrial cup development and PMSG and progestagen production in equids. The influence of fetal genotype upon gonadotrophin (PMSG) and progestagen production in mares and donkeys during the first half of pregnancy was examined. The production of PMSG was greatly reduced in mares carrying mule conceptuses and greatly increased in donkeys carrying hinny conceptuses. Fetal genotype had no obvious influence upon progestagen production in mares, but donkeys carrying hinny conceptuses showed extremely high peripheral plasma progestagen concentrations when serum PMSG levels were elevated. Fetal genotype profoundly influences the intensity and rate of success of the maternal leucocyte response directed against the endometrial cups. The suggestion is advanced that PMSG may constitute an immuno-protective barrier around endometrial cup cells which partly protects the cells from attack by sensitized maternal lymphocytes.


Plasma progestagens in pregnant mares.

Plasma progestagens in pregnant mares. Peripheral plasma progestagens were quantified by a competitive protein-binding assay throughout pregnancy. The level of progesterone increased significantly between Days 0 and 8 (P less than 0-05) and again between Days 28 and 44 and reached a maximum on Day 64. Subsequently, it fell slowly until about Day 300 and then rose again during the last 30 days before reaching a minimum on the day after foaling. Very low concentrations of 17alpha-hydroxyprogesterone were found except between Days 40 and 120 and during the last 30 days before birth. Two unidentified compounds, one eluting slightly before and one after progesterone on Sephadex LH-20 columns, first appeared in plasma between Days 30 and 60 of gestation, and increased gradually to Day 300. Both compounds increased significantly (P less than 0-05) at about 5 days before birth and were not detectable on the day after foaling.


Ovarian changes during early pregnancy in pony mares in relation to PMSG production. The ovaries of twenty pregnant mares were examined daily, per rectum, for the first 4 months of gestation and note was made of their estimated size and follicular content. Serial blood samples from sixteen of the mares were assayed for PMSG. A marked seasonal effect was noted on ovarian size, follicular content and ovulation rate during pregnancy but there was no such effect on PMSG production. It is concluded that PMSG is synergistic with gonadotrophins of pituitary origin and that the latter hormone are the primary stimulus on the ovary of the pregnant horse.


Plasma progestagens in the pregnant mare in the first and last 90 days of gestation. Plasma progestagens were measured in eighteen pregnant mares to establish normal levels in the first and last 90 days of gestation. Progestagens increased from 25 ng/ml at 90 days before birth to 60 ng/ml at 10 days before birth, decreased to 58 ng/ml at 5 days before, and were 3 ng/ml or less by 5 days after perturition. During the first 90 days of pregnancy, progestagens reflected luteal activity with an increase in plasma levels from Day 30 to Day 60.


Plasma progestagens in cyclic, pregnant and post-partum mares. The pattern of plasma progestagen levels during the oestrous cycle was similar to that previously reported except for lower peak levels. The lack of significant difference (p less than 0-01) between CPBA and RIA values suggests that progesterone itself is the major component during the oestrous cycle. Progesterone levels during the first and second post-parturient oestrous cycles were similar to those observed during the cycle of the non-pregnant mare. During pregnancy there were two peaks of plasma progestagens. The first, which occurred during the 3rd month, coincided with high levels of PMSG and was probably produced by the endometrial cups or the secondary CL. The second peak occurred in the 11th month and probably represented the secretion of placental progestagens. At least two unknown progesterone (?) metabolites were present which cross-reacted in the CPBA and RIA systems and probably contributed to the high progestagen values obtained in late pregnancy when chromatography was excluded from the assay procedures. Progestagen levels dropped precipitously after parturition and was probably due to placental separation from the endometrium. The higher progesterone levels in the newborn foal and other evidence suggests that this hormone is produced by the fetal gonads.


Follicular and luteal development in pregnant mares. Examination of the ovaries of mares at various stages of pregnancy and after hysterectomy, together with measurement of progesterone concentrations in the peripheral plasma of pregnant and hysterectomized mares and in uterine and ovarian venous plasma of pregnant mares, demonstrated that the primary CL of pregnancy remains functional until at least Day 160 of gestation. The results showed that primary and secondary CL, and the placenta or uterus, all contribute to the total progesterone pool in mares during pregnancy. Similarities and differences in ovarian function observed between pregnant and hysterectomized mares suggested that, while PMSG does not appear to stimulate follicular development, it does prolong the life-span and stimulate the secretory activity of the primary CL, and induces ovulation and/or luteinization of secondary follicles in pregnant mares.


Endocrine patterns of the mare at term.

Endocrine patterns of the mare at term. The levels of progesterone and total progestins increased during late pregnancy and then fell dramatically during the last few days before parturition, although birth occurred in the presence of significant amounts of plasma progesterone. Oestrogen levels decreased slowly but insignificantly until birth occurred, and then remained at a low level until the post-partum oestrus 10 to 12 days later. Total 11beta-hydroxycorticosteroids were unchanged from Day 45 before to Day 15 after birth. The endocrine pattern of one ovariectomized pregnant mare during the last month of gestation was similar to that of the intact mares. A normal cyclic progesterone and total progestin pattern was observed at the post-partum ovulation. Oestrogen levels did not change significantly but corticosteroid levels increased significantly between Days 15 and 22 post partum. Progestin, oestrogen and corticosteroid levels during the first 24 hr after birth were consistently higher in the foal than in the maternal plasma.


Factors influencing foaling percentages in Australian mares. Foaling figures for Thoroughbred mares in Australia show a puzzling disparity between conception and foaling rates in the second half of the 22 years of official data collection between 1950 and 1972. In the first 9 years of the survey, the live foal percentages rose in parallel with conception rates, but then a divergence of the figures occurred with the conception rate continuing to improve by 6-25% while the foaling rate improved by only 0-01% over the same period. An hypothesis supported by data from two studs is considered that stress factors additional to those experienced by mares in the earlier years may be responsible for the regression of the foaling figures.


Biochemistry of stallion semen.

Biochemistry of stallion semen. Stallion semen has several chemical characteristics not commonly encountered in other animals. It contains very little fructose and the spermatozoa possess only limited fructolytic ability under anaerobic conditions. By determining some of the characteristic constituents such as ergothioneine, citric acid, glycerylphosphorylcholine and certain glycosidases, it is possible to obtain a quantitative measure of the secretory contribution of the ampulla, seminal vesicle and epididymis, respectively, towards the final composition of the whole ejaculate. By analysing separately the various fractions of a split ejaculate, including the so-called tail-end sample, it is possible to detect and pinpoint abnormalities in the functional state of the various male accessory organs and in the entire process of ejaculation.


Comparison of the methods of rectal palpation and haemagglutination-inhibition assay for diagnosis of pregnancy in mares. The diagnostic value of rectal palpation and immunological assay of PMSG was tested at different stages of pregnancy in mares inseminated with frozen semen in three separate studies. The results were based on foaling success and particular attention was paid to the numbers of inconsistent results obtained by the two tests. Generally, the number of false positive diagnoses was lower for the immunological assay than for palpation in early pregnancy (Days 40 to 60) and the relationship became reversed later in gestation.


Oestrone and equilin in the plasma of the pregnant mare. A method for the extraction of oestrone and equilin from the plasma of the pregnant mare is described, and the levels obtained for eighty-two samples from fourteen Welsh Mountain Ponies at different stages of pregnancy are recorded. Oestrone (fifteen samples) and equilin (three samples) were not found before Day 120. From Day 120 to 240, oestrone levels exceeded 100 ng/ml and then declined to parturition. The high concentrations of oestrone in mid-pregnancy were associated with gradually increasing concentrations of equilin which tended to plateau after Day 180 at just under 100 ng/ml and declined significantly only in the last month of pregnancy. Evidence is presented that both oestrone and equilin occur in peripheral plasma largely as sulphates.


Early pregnancy testing and its relationship to abortion. A total of 487 Standardbred and Thoroughbred mares at two studs were manually tested for pregnancy at 20 to 24, 30 to 34, and greater than 42 days after service and the abortion rate compared to that obtained in previous years when only the greater than 42-day test was performed. The results indicated that early manual pregnancy testing does not increase the abortion rate if undertaken carefully and enables non-pregnant mares to be re-mated earlier in the same season.


Oestrogens, LH, PMSG, and prolactin in serum of pregnant mares. Levels of oestrone, equilin and equilenin (E1), oestradiol (E2) LH, PMSG and prolactin were measured by radioimmunoassay in serum from pregnant mares. Levels of E1 were always greater than those of E2. Both E1 and E2 remained at low levels until Day 80, increased significantly (P less than 0-05) by Day 120 to reach peak levels at Day 210 or 240 and then declined until parturition. Maximum levels of oestrogens observed in this study were 828 +/- 151 pg/ml for E1 and 71 +/- 18 pg/ml for E2 at Days 210 and 240 respectively. Spikes of LH release were observed in early pregnancy in most mares. Levels of PMSG were first detectable at Days 32 or 36 and reached a peak of 67-1 i.u./ml 64 days after the last mating. Levels of LH were very low (often non-detectable) from Day 210 of gestation until parturition. Levels of prolactin were extremely variable and showed no clear fluctuating patterns during pregnancy.


Early embryonic development in the horse.


Retention of tubal eggs in mares.

Retention of tubal eggs in mares. Genital tracts from 227 mares slaughtered in various reproductive states were investigated to study egg retention in the oviducts. Eggs were found in 88-2% of 212 non-pregnant mares; the number/mare ranged from 0 to 21, and averaged 4-34. Retained eggs were twice as common in heavy as in light breeds and were found more frequently in early than in late pregnancy. Eggs were not found in the oviducts of two anovulatory post-partum mares. A few globular masses, probably consisting of desquamated tubal mucosa, were frequently lodged in the distal region of the ampulla and appeared, to some extent to cause the retention of more eggs.


Development of the equine fetus and placenta. Prenatal specimens from mares with known breeding dates were used to characterize morphological changes in the fetus and placenta of pony mares. Prenatal characteristics and the day on which each was first found and weights of different components of the equine conceptus are summarized.


Embryological studies on the dartmoor pony during the first third of gestation. A sequence of ten known-age embryos recovered from Dartmoor Ponies during the first 4 months of gestation is described. Changes in size, shape and vascularity of the conceptus are recorded, as well as the growth and decline of the yolk-sac and the succeeding establishment of the allantochorion. The progress of equine somatogenesis is compared with that of the pig which it lags on average of about 4 days. Some quantitative data are presented.


A survey of eggs in the oviducts of mares. A total of 424 eggs was recovered from flushings of 176 pairs of oviducts. Of these eggs, 324 were in a state of advanced degeneration (Type 4) and ten appeared to have been recently ovulated (Type 1). The number of eggs/oviduct varied from 0 to 13, most being up to 3 eggs, but fifty oviducts contained no eggs. It is widely believed that unfertilized ova are selectively retained in the oviducts but an alternative explanation for their presence is put forward.


Spermatogenesis and duration of transit of spermatozoa through the excurrent ducts of stallions. The cycle of the seminiferous epithelium was divided into eight stages on the basis of meiotic divisions, shape of the spermatid nuclei and location of the spermatids with elongated nuclei. Duration of this cycle was 12-2 days (S.E. +/- 0-1) as determined by [3H]thymidine injections and autoradiography. The life-span of primary spermatocytes was 19-0 days, secondary spermatocytes 0-7 days, spermatids with round nuclei 8-7 days, and spermatids with elongated nuclei 10-1 days. Labelled spermatozoa entered the caput epididymidis 35 days, and appeared in the ejaculate 39-9 days, after the isotope injection. The mean minimal time required for spermatozoa to pass through the excurrent ducts was 4-9 days. However, the average transit time was estimated to be between 8 and 11 days. Variation in the duration of the cycle between species is discussed.


A surgical technique applied to the study of tubal eggs in the mare. An efficient surgical technique of collecting eggs from the oviducts of mares is described. Within 6 days after ovulation recovery was successful in 22/29 mares. The technique has been used to investigate the retention and ageing of eggs in the oviducts and to determine the origin and the nature of the accessory CL during pregnancy.


Observations on reproductive performance in the yearling mare. Reproductive performance was studied in 137 yearling mares run with stallions in small groups for 3 months between June and August in 1968 to 1971 (four breeding seasons). Pregnancy diagnosis by repeated rectal palpation and qualitative tests for PMSG, showed that ninety-five mares conceived of which forty-four aborted spontaneously between Days 30 and 160 of gestation. Laboratory examination of twenty-one aborted fetuses failed to show any infectious agents. Serial quantitative and qualitative tests for PMSG in aborting animals gave results similar to those observed in mares with normal pregnancies. Plasma progestagen assays showed marked individual variations although the loss of the conceptus was always associated with a drop in progestagen level. The high incidence of early pregnancy loss in these pubertal mares may also be related to immaturity, inadequate nutrition and physical stress.


Ovulation and transuterine migration of the conceptus in thoroughbred mares.


The occurrence of early embryonic death in the mare in relation to natural service and artificial insemination with fresh or deep-frozen semen.


Surgical and non-surgical egg transfer in horses. Surgical and non-surgical methods used for the recovery and transfer of fertilized horse eggs are described. Sixteen of the twenty-three zygotes recovered surgically between Days 1 to 6 after ovulation from thirty donor mares were transferred surgically to synchronized recipients; seven pregnancies resulted. Seven of the eleven zygotes recovered non-surgically between Days 6 to 8 after ovulation from twenty-eight donor mares were transferred non-surgically to synchronized recipients; five pregnancies resulted.


Observations on the time of foaling in thoroughbred mares in Australia.


An ultrastructural and histochemical study of the interstitial cells in the gonads of the fetal horse. Gonadal tissue obtained at about 50-day intervals from Days 60 to 300 of gestation was examined histologically, histochemically and in the electron microscope. The marked enlargement of the gonads (ovaries or testes) reached a peak around Day 250 and was caused by hypertrophy and hypoplasia of interstitial cells. These cells had all the ultrastructural characteristics of a steroid-secreting cell but delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) was not detected at any stage of their development. There was no significant change in the ultrastructure of the interstitial cells between Days 100 and 250 except for a progressive increase in the number of dense bodies. By Day 300 the fetal gonads had begun to regress and degenerative changes were apparent in the interstitial cells. The possible mechanisms controlling the growth of the fetal gonads and their function in steroidogenesis is discussed.


Germ cell development and the meiotic prophase in the fetal horse ovary. A histological study of the developing germinal epithelium in the fetal horse ovary shows an enormous wastage of oocytes during the meiotic phase, between Days 73 and 150 of pregnancy. The first groups of oocytes to enter this phage undergo mass degeneration and eventually disappear; few, if any, oocytes develop to primordial follicles. Peripheral oogonia, dividing by mitosis, give rise to more oocytes which pass through the same changes and are also reduced by degeneration, but by Day 150 primordial follicles are fairly common.


Development of pituitary and adrenal glands in the fetal horse. The various cell types in the adult anterior pituitary may be distinguished at the ultrastructural level of the sizes of the secretory granules within the cytoplasm. In the fetal adenohypophysis, with the exception of prolactin-producing cells, all types may be identified after Day 100 of gestation. Morphological evidence suggests that they are producing and secreting trophic hormones. The three constituent layers of the adrenal cortex are also discernible by Day 100 of pregnancy. The cells of the zona glomerulosa have large numbers of darkly stained inclusions within the cytoplasm. The zona fasciculata shows changes consistent with the production and secretion of steroid hormones.


A histochemical study of steroid metabolism in the equine fetus and placenta. The distribution of several hydroxysteroid dehydrogenases (HSD) was examined in a variety of equine placental and fetal tissues. The main points of interest were: (a) the lack of dehydrogenase activity in the gonad, (b) the appearance of a variety of HSDs in the trophoblast as early as 13 days of gestation, (c) the histochemical similarity between the cells of the trophoblast and the endometrial cup, and (d) the restriction of the strong endometrial 17beta-HSD reaction to those parts of the uterine epithelium directly apposed to the trophoblast.


Fine structure of the gonads of the horse and its functional implications. Light and electron microscopic studies of the gonads of the fetal horse have shown that, in their hypertrophic condition which begins during the 3rd month, the interstitial cells contain large amounts of smooth endoplasmic reticulum, suggesting a secretory activity. Hydroxylating activity which was cytochrome P-450-dependent was observed in the fetal testis and may be involved in steroid biosynthesis.


Ultrastructural development of the equine placenta. Microcotyledons, which are a distinctive feature of the mature equine placenta, are fully formed by Day 150 of gestation. The fetal component of each microcotyledon is developed from several primary folds of trophoblast which become elaborately subdivided as gestation proceeds. These changes are reflected in the structure of the maternal crypts, which receive the fetal villi. Between Days 60 and 150 of gestation the maternal epithelium is greatly reduced in height. No such change occurs on the fetal side of the placenta, but between Days 100 and 250 a progressive indentation of the epithelium by fetal capillaries reduces the effective thickness of the placental barrier. The ultrastructural characteristics of fetal and maternal epithelia are described.


Anatomy of the placental barrier in the mare. The study of the equine placenta, which began in Venice in 1598, has a long but discontinuous history. Early observations were purely morphological, but new techniques have stimulated a broader and more functional approach. Histological and ultrastructural observations at various stages of pregnancy have shown that the fetal side of the placenta comes to acquire certain features in common with the air-blood barrier of the mammalian lung. These changes may reflect the increasing O2 requirements of the fetus as gestation proceeds.


The use of intravascular catheters for long-term studies on the mare and fetus. Methods developed for the insertion of catheters into the umbilical artery and vein and the uterine vein of the pregnancy mare are described. The technique requires careful anaesthesia and the maintenance of normal blood gas tensions, pH and arterial blood pressure. Fetal survival was variable: three mares delivered live foals and six fetuses survived more than 15 days with a maximal period of 41 days. The erythrocytes sedimentation rate (ESR) of the fetal foal was always very low at operation but subsequently increased slightly; a sudden large rise in ESR usually indicated imminent fetal death. The relatively sudden death in utero of catheterized fetuses maintained for 10 days or more remains unexplained. Nevertheless, the stability and relatively long duration of some of these preparations are sufficient to investigate various aspects of placental exchange and the endocrine climate of the fetus.


Characteristics of the successive jets of ejaculated semen of stallions. The use of an 'open' artificial vagina made it possible to separate the individual jets in the ejaculate of the stallion. A total of 132 jets were collected in this way from twenty-one ejaculates. After macro- and microscopic examination and sperm counting, glycerylphosphorylcholine (GPC), ergothioneine and fructose levels were determined for every jet. The values obtained for the first three jets were similar and accounted for about 76% of all spermatozoa, and 70% of GPC. These jets also contained the highest concentration of ergothioneine and fructose.


Morphology and pathology of the equine umbilical cord. A brief description is given of the morphology of the umbilical cord and some variations encountered. In 95% of normal Thoroughbred foals the cord measures less than 84 cm. Factors which govern cord length are not known. Seven pathological conditions involving the umbilical cord are described. Increased length is the most common abnormality and predisposes to three potentially lethal conditions, strangulation of the cord around the fetus, excessive torsion, and allantochorionic necrosis at the cervical pole.


Plasma progestagens and oestrogens in fetus and mother in late pregnancy. Normal Thoroughbred and catheterized Pony mares and their fetuses were used. Fetal oestrogen and progestagen concentrations in late gestation were much higher than maternal values. A major feature of the umbilical steroid concentrations was a large venous-arterial difference in progestagens and total oestrogens throughout late gestation which may indicate a metabolic cycle in the fetus between progesterone and other steroid metabolites. Metabolites of 20alpha-dihydroprogesterone were present in high concentrations in maternal and fetal plasma. In Thoroughbreds, and to a lesser extent in Pony mares, plasma progestagens rose towards parturition while total plasma oestrogen fell. The only oestrogen which showed a rise in concentration near term was oestradiol-17beta. In one Pony mare and fetus, fetal plasma progestagen fell 24 to 36 hr before parturition when maternal peripheral progestagen concentrations remained high.


Ontogeny of equine haemoglobins.

Ontogeny of equine haemoglobins. Studies were made of the O2 affinities of fetal and maternal haemoglobins in the horse, and correlations were found with erythrocytic levels of 2,3-diphosphoglycerate.


Studies on fetal, neonatal and maternal cortisol metabolism in the mare. Fetal plasma cortisol concentrations (mean +/- S.E.M.) in ten animals with indwelling umbilical catheters ranged from 13-9 +/- 1-5 ng/ml (227 to 244 days) to 18-1 +/- 2-2 ng/ml (290 to 310 days). Maternal values did not change over this period (15-9 +/- 1-7 ng/ml). Fetal cortisol production rates in two fetuses were 3-6 and 3-8 mg/kg/day at 291 days; there was little placental transfer of cortisol. In three fetuses (319 to 321 days) plasma cortisol values 1 to 10 days before birth were higher (30 to 50 ng/ml) than in any other group, and at birth the values were comparable with those found in intact Thoroughbred foals at birth. After birth plasma cortisol concentrations fell rapidly in most foals, but very high values were found in two foals with postnatal convulsions. Plasma cortisol levles remained low in two Thoroughbred foals born prematurely: similar values were found in one catheterized foal both before and after parturition.


Sperm transport and distribution in the mare. Fifty mares were inseminated on Days 2, 4, 7, 11 or 17 of the oestrous cycle with spermatozoa from one of three stallions to observe the distribution of the spermatozoa in various parts of the reproductive tract 12 hr later (Days 3, 5, 8, 12 and 18). Only 0-06 to 2-21% of inseminated spermatozoa were recovered from the tract. More (P less than 0-05) spermatozoa were recovered from the cervix and uterus on Day 12 than on Days 3, 5, 8 and 18. The mean number of spermatozoa recovered from either or both oviducts was significantly greater (P less than 0-10) on Days 5 and 8 than on Days 3, 12 and 18. More spermatozoa were recovered from the right than the left oviduct and the number recovered from the oviducts was significantly (P less than 0-05) influenced by the stallion.


Studies on mild composition and lactogenic hormones in the mare. Small samples of mammary secretion were collected from eight Thoroughbred mares during the last week of pregnancy, at foaling and after 1 week of lactation. Specific assays showed the presence of both lactose and triglyceride in all samples before birth and progressive increases in their concentrations in colostrum and in milk. Levels of 6-0 g lactose/100 ml and 1-8 g triglyceride/100 ml were present in milk at 7 to 9 days post partum. The secretory capacity of the udder is thus normally established well before parturition in the mare. Attempts to demonstrate the occurrence of a placental lactogen and to measure lactogenic hormones in plasma have been unsuccessful.


Patterns of urinary oestrogen excretion in individual pregnant mares. Urine collections (24 hr) were made at weekly intervals from four Pony mares from the 3rd or 4th month of pregnancy until parturition. Separation of oestrogens on Celite columns was followed by Kober measurements of oestrone and equilin. Individual differences were noted in peak amounts of total oestrogens excreted (200 to 800 mg/day), when oestrone constituted 80 to 95% at the 6th to 7th months. Although equilin increased in later gestation, oestrone remained the major product. Total oestrogen values decreased rapidly from the peak and then more gradually towards the end of pregnancy. During the last 3 weeks the decline in the ratio of oestrone to equilin was reversed in all mares.


The effect of a corticosteroid (dexamethasone), progesterone, oestrogen and prostaglandin F2alpha on gestation length in normal and ovariectomized mares. Dexamethasone (100 mg/day) injected from Days 318 to 324 of pregnancy induced parturition. Progesterone (500 mg/day) administered daily from Day 318 of pregnancy also shortened gestation while oestrogen (50 mg/day) administered on the same schedule as progesterone had no such effect. Dexamethasone treatment superimposed on the oestrogen or progesterone treatments shortened gestation. Prostaglandin F2alpha alone did not induce parturition, unlike PGF2alpha with dexamethasone, or PGF2alpha given to ovariectomized mares.


The development of the lung and its surfactant in the foal and in other species. The development of the lung from the glandular through the canalicular to the alveolar stages in the horse fetus is described. Traces of surfactant and occasional lamellated osmiophilic bodies representing intracellular surfactant were found at 150 days of gestation, some 40 to 60 days before the transition to the canalicular stage. During this transition some of the cuboidal cells of the glandular rosettes are transformed into cells of Types I and II, but the surfactant is not fully developed until 300 days or, in some foals, until after delivery.


Induction of parturition in mares.

Induction of parturition in mares. Thirty-seven induced parturitions involving thirty-one mares were studied over a 2-year period using various doses of oestrogen and oxytocin. The time of appearance and degree of expression of the major clinical signs of parturition, and the time for completion of delivery and the passage of the placenta were significantly influenced by increasing doses of oxytocin. Oestrogen was useful in softening and relaxing the cervix when it was tight, but was not essential to induction when the cervix was already soft and dilating. Fertility was not adversely affected by induced parturition.


Surfactant studies in the fetal and neonatal foal. Phospholipids in embryonic lung tissue, pulmonary washings and amniotic fluid were measured to study the development of lyng surfactant in the horse. A significant increase in the concentration of total phospholipids in lung tissue and a concomitant rise in the amount of dipalmitoyl lecithin in amniotic fluid between 100 and 150 days of gestation indicated the initial formation of surfactant in the fetal lung during this period.


Postnatal lung growth and function in the foal. Respiratory function in newborn foals is discussed with particular reference to the important part played by functional residual capacity and chest wall compliance in maintaining blood gaseous exchange within normal limits.


The lung surfactant: an introduction.

The lung surfactant: an introduction.


Studies on pressure-volume relationships in excised equine lungs. Forty-eight lungs from fetal and neonatal horses were examined for pressure-volume relationships between pressures of 0 and 40 cmH2O. The inflation-deflation curves obtained were analysed by four different methods and the stability of the lung assessed in terms of hysteresis, stability indices and volume of air retained at maximal pressure (Vmax). Differences in the shape of the deflation curve between ventilated and non-ventilated lungs were similar to findings in other species. It is postulated that breathing alters lung-tissue elasticity during the neonatal period, as demonstrated by a significant increase in Vmax in specimens from foals breathing for more than 24 hr compared with those from stillborn foals or those aged less than 24 hr. Also, stability indices, such as those expressed by the % of air retained in the lungs on deflation from Vmax to 10 or 5 cmH2O pressure, are related to interfacial factors.


Aspects of respiration in anaesthetized newborn foals. The arterial oxygen tension (PaO2) in clinically normal newborn foals at 1300 m above sea-level is considerably lower (less than 60 mmHg) than in similarly aged foals at lower altitudes. This figure is further reduced to less than 50 mmHg without adverse effect in newborn foals at 1300 m maintained under pentobarbitone anaesthesia for prolonged periods. Measurement of O2 dissociation curves indicates that haemoglobin becomes saturated at a lower blood O2 tension in newborn foals than adult horses.


Neuropathology of the convulsive foal syndrome. Brains from eighteen Thoroughbred foals suffering from the convulsive foal syndrome were examined neuropathologically and compared with brains from nine foals dying from different causes. In the brains of nine convulsive foals there was necrosis of the cerebral cortex, accompanied in three by severe necrosis of the diencephalon and brain stem; haemorrhage into the cerebral cortex was also present in most of this group. In the other nine brains from convulsive foals there was haemorrhage, often severe, especially in the white and grey matter of the cerebral cortex and in the cerebellum. Minimal haemorrhage occurred in the brains of the control group of animals, except in that from one Caesarian-delivered premature foal that suffered severe haemorrhage into the brain stem and cerebellum. Both types of lesion in the convulsive foal appeared to be related to events occurring just before, during or after birth.


Preliminary observations on cranial cardiovascular changes during asphyxia in the newborn foal. This paper describes preliminary experiments designed to test the hypothesis that cerebral damage is caused by cardiovascular events involving explosive changes in cerebral blood flow during birth. These events may be responsible for the convulsive episodes of foals suffering from the neonatal maladjustment syndrome.


Social organization and reproduction in equids. There are two distinct types of social organization and, accordingly, two types of mating systems in equids. In the horse, Plains zebra and Mountain zebra, the adults live in non-territorial and cohesive one-male groups and in stallion groups. The family stallions have exclusive mating rights which are respected by all others. In Grevy's zebra and in the African and Asiatic wild asses, the stallions are permanently territorial and have exclusive mating rights within their territories. Ecological and evolutionary aspects are discussed.


Metabolic profiles of newborn foals.

Metabolic profiles of newborn foals.


Postnatal changes in total and free thyroxine and triiodothyronine in foal serum. Total tyhroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3) and free triiodothyronine (FT3) concentrations in foal umbilical cord blood were respectively 14, 5 7 and 3 times the concentrations of these hormones in adult horse blood. The TT4 levels in foals declined rapidly to reach adult concentrations by Day 16 and FT4 levels declined steadily during the first 3 months of life. Foal TT3 levels rose during the first 10 hr after birth and thereafter declined, although they were still X2-5 higher than adult levels at 3 months of age. Levels of FT3 similarly increased after birth becoming X8 higher than adult levels at 3 days of age. They declined after this time but were still twice the normal adult levels at 3 months of age. Associated with these age changes were an increase in the free hormone percentage and a decrease in binding protein concentration. The very high levels of thyroid hormones in newborn foals may be responsible for their extremely high thermogenic capacity and rapid pre- and post-natal rates of growth, especially of the musculo-skeletal and nervous systems.


The development and distribution of mucosal enzymes in the small intestine of the fetus and young foal. Lactase and cellobiase were detectable in the fetal intestine by the 3rd month of gestation, and although there was little change by the 9th month, maximal levels were reached at birth and steadily declined after 4 months. Conversely maltase, sucrase and trehalase were barely discernible in the fetus, maltase being present at low levels at birth, but all increased during the suckling period to attain adult levels by 7 months of age. Alkaline phosphatase activity matured earlier than did disaccharidase activity. Mucosal enzymes other than alkaline phosphatase were virtually absent from meconium and the large intestine. Continued ingestion of lactose could be detrimental in foals suffering from severe diarrhoea.


The transfer of passive immunity to the foal and its relation to immune status after birth. The mechanism of transfer of maternal immunity to the foal is reviewed. Maximal efficiency of macromolecular absorption by specialized cells of the small intestine exists soon after birth. The absorptive cells are progressively replaced by more mature-looking cells incapable of taking up large molecules and the rate of absorption is reduced in a linear decline and ceases completely within 24 hr. Passive antibody levels fall rapidly in the first 4 weeks of life to less than half their original values and have usually completely disappeared by 6 months of age. The foal shows immunological competence soon after birth although appreciable levels of autogenous immunoglobulins are not usually attained until 2 to 3 months of age.


Babesiosis in the newborn foal.

Babesiosis in the newborn foal. A short account is given of babesiosis (equine biliary fever) caused by the tick-borne protozoan Babesia equi and B. caballi, endemic in the Cape Province of South Africa. The clinical picture, diagnosis and treatment are described. In the absence of any prophylactic measures, prognosis is poor; control of the parasites in the tick-infested areas is essential.


Immunoglobulin metabolism in the neonatal foal. The proteins IgG and IgG(T) are the predominant immunoglobulins in equine colostrum. Their distribution and catabolism were studied in the newborn foal using an isotopic tracer technique. More precise quantitation of the absorption of these immunoglobulins from colostrum is now possible.


Immunoglobulins produced by the antigenized equine fetus. The foal is born without detectable antibody and except for small amounts of IgM is devoid of immunoglobulins. Intrafetal administration of either Venezuelan equine encephalomyelitis virus (VEE-TC83) or ovine erythrocytes elicited IgGa, IgGb and a trace of IgG(T). The fetal blood VEE-TC83 neutralization titre was higher than the neutralization titre elicited by the same preparation in older horses.


The gnotobiotic foal in the study of infectious diseases. A method of rearing germ-free gnotobiotic foals is described. To date, four foals have been infected with rhinopneumonitis and the only clinical signs of infection have been a transient fever and leukopaenia; no detailed results are, as yet, available.


Semen characteristics in thyroidectomized stallions. Three Quarter-horse stallions were surgically thyroidectomized at 18 months of age. Weekly semen collections were made from these and three control stallions from 25 to 39 months of age. Although the induced state of hypothyroidism in young stallions has a depressing effect on libido and general animation and can be corrected by thyroprotein supplementation, semen characteristics, testicular histology and fertility are not affected by the operation.


A study of the morphology of stallion semen during the breeding and non-breeding seasons. Season was shown to markedly influence semen characteristics of stallions in Holland, including ejaculate volume, sperm motility, total number of spermatozoa/ejaculate and the percentage of spermatozoa showing morphological abnormalities. Maintenance of normal stallions in continuous light during the winter months and administration of a vitamin and mineral supplement to sub-fertile stallions before the start of the breeding season appeared to improve spermatogenesis significantly.


The effect of semen extenders and sperm number on mare fertility.


Studies on the preservation of raw and frozen horse semen. Retention of high motility of horse spermatozoa preserved at 4 degrees C was improved by a semen extender. Raw semen preserved for 2 to 8 hr at 4 degrees C gave an average conception rate of 67-3% but preservation for 1 to 2 days gave an extremely low conception rate. The conception rate from deep-frozen semen during 8 years was 56-3%.


Cure expectancy in children with acute lymphoid leukemia.


Legal penalties for possession of regulated substances.


First aid training is vital for effective emergency medical services.


Medicine's "future shock".

Medicine's "future shock".


Editorials: Medicine, Russia, shock, and the future.


Carcinoma of the thyroid. 20 year experience at the Spartanburg General Hospital.


Clinical conference: Clinicopathological conference of the Medical University of South Carolina. Abdominal mass with death from shock in 80 year old woman.


Quest for uniqueness. What makes the Medical University of South Carolina different?


Editorial: Tick tock, tick tock.

Editorial: Tick tock, tick tock.


Considerations in cosmetic plastic surgery.


Combination of membrane oxygenator support and pulmonary lavage for acute respiratory failure. A 24-year-old woman with chronic granulocytic leukemia and alveolar proteinosis required extracorporeal membrane oxygenator support for respiratory failure refractory to conventional therapy. During perfusion, each lung was lavaged with 10 L. of normal saline. The lavage led to marked clearing of the lungs and improvement in pulmonary function. Extracorporeal support was terminated successfully after 54 hours. The patient died 2 weeks later with bone marrow insufficiency and overwhelming sepsis. Pulmonary lavage is technically feasible during venovenous oxygenator bypass, and may be of value, since such lavage debrides alveoli as well as the bronchial tree. Because pulmonary lavage provides a possible means of improving pulmonary function, it seems worthy of consideration as an adjunct to membrane oxygenator support.


Resection of two vital roots.

Resection of two vital roots.


Effect of instrumentation on the shape of the root canal.


Hematology mediquiz. What's your diagnosis?


Dihydrofolate reductase deficiency causing megaloblastic anemia in two families. To determine the cause of severe megaloblastosis detected at birth and at four weeks in two unrelated infants their bone marrow and liver cells were studied. Both patients had abnormal deoxyuridine suppression tests, corrected to normal by 5-formyl tetrahydrofolic acid. Liver-cell homogenate from one patient had a previously undetectable level of dihydrofolate reductase restored to normal by high cation concentration in the assay. Activity of the liver-cell homogenate from the other patient, which was one quarter of the normal level, was restored to only half normal activity by high cation concentration. Dihydrofolic acid reductase deficiency prevents this conversion of folic acid to tetrahydrofolic acid; the enzyme activity appears to differ in each patient. A satisfactory clinical response in both patients followed parenteral therapy with 5-formyl tetrahydrofolic acid. One sibling in each family died of a similar illness. Autosomal recessive inheritance is probable.


Adult-onset acid maltase deficiency. Morphologic and biochemical abnormalities reproduced in in cultured muscle. We established muscle-tissue cultures from biopsy of a patient with adult-onset acid maltase deficiency. Morphologically and biochemically, the newly grown fibers of the cultured muscle showed the same abnormalities as those of the biopsied muscle. Light microscopy showed multiple vacuoles filled with acid-phosphatase-positive material; on ultrastructural examination there was abnormal accumulation of glycogen in membrane-bound sacs (secondary lysosomes), some of which also contained dark membranous of homogeneous material. Acid maltase (pH 4.0), a lysosomal enzyme, was undetectable in either cultured or biopsied muscle by maltose hydrolysis, whereas acid phosphatase, also a lysosomal enzyme, was increased in both sources of muscle cells. Cultured muscle fibers demonstrate the same morphologic and biochemical abnormalities characteristic of biopsied muscle, supporting the concept of a biochemically distinct primary myopathy in man.


Colony formation in vitro by leukaemic cells in acute myelogenous leukaemia with phytohaemagglutinin as stimulating factor.


A sense of satisfaction about 1975.

A sense of satisfaction about 1975.


Medical and psychiatric services. Consolidated system of delivery based on community treatment programs and community facilities.


Ampicillin in man. Adverse effects.

Ampicillin in man. Adverse effects.


Hypertension in high school students. Evaluation in New York City.


Physician referral failure. Study of home care.


Unrealistic patient.

Unrealistic patient.


Outpatient treatment of tuberculosis in unreliable alcoholic patients.


Electrocardiograms of the month.

Electrocardiograms of the month.


Popliteal artery entrapment syndrome.

Popliteal artery entrapment syndrome.


Systemic lupus erythematosus and carcinoma of lung.


Benign polyposis treated by total gastrectomy.


Clinical psychopharmacology and the elderly patient.


Arterial hemorrhage complicating pelvic fracture.


Sexual activity and contraception use in young adults. 241 (57 male and 184 female), well-educated, largely urban, young persons, voluntarily attended a lecture on sex; after the lecture they completed an anonymous questionnaire on their background, and attitudes to sex. A majority believed that premarital sexual activity was acceptable if there was some affectional tie between the couple. Most of the men were sexually active, while only a third of the women were so. However, a quarter of the sexually inexperienced men and women were engaging in forms of sexual stimulation which would seem to carry a high possibility of ending in intercourse. Knowledge of contraception, while high, tended to over-estimate the efficacy of the safe period and vaginal methods. Half the sexually active group had used contraception at sexual initiation but only a third had used reliable methods. Subsequent contraceptive practice however, was high (90 percent), with the pill being the most frequently used method. Twenty percent of the sexually active women had already been pregnant: of these only a quarter had carried their pregnancies to term. The limitations of the study are discussed and some suggestions for preventing pregnancy in the unmarried drawn.


The diagnosis of organic tricuspid valve disease. Diagnostic features of organic tricuspid valve disease are discussed with emphasis on clinical features. Cardiac catheter data show considerable differences in assessment as do the chest radiographs. Measurement of the right atrial border from the vertebral edge is a reliable guide to diagnosis.


The evaluation of continuing medical education. To use the limited time available for the most benefit, practising doctors need presentations of maximal educational effectiveness. This effectiveness can be assessed by methods which are practical and acceptable. We can evaluate the educational process itself by assessing each presentation using selected criteria, by examining the appropriateness of programme content, and by obtaining the opinions of participants. We can evaluate changes in the knowledge of participants by seeking opinions from them and by building evaluation into educational sessions. We can look at patient-outcome in relation to education by seeking the opinions of informed observers and by building evaluation into clinical work.


Ethanolamine oleate and acute renal failure. Two patients suffered from acute renal failure following the use of a larger than usual volume of ethanolamine oleate during the injection of varicose veins. Prominent symptoms of headache, nausea and epigastric pain were associated with the onset of acute renal failure. Spontaneous recovery occurred.


Editorial: Bence Jones proteinuria.

Editorial: Bence Jones proteinuria.


Letter: Nitrazepam and auricular fibrillation.


Editorial: Growth of the New Zealand child.


New Zealand trends in rheumatic fever: 1885-1971. National statistics of rheumatic fever in New Zealand show falling mortality over the past 30 years. However, morbidity remains high, especially among Maori children. Community-based studies are under way to elucidate this important public health problem.


Letter: Intravenous solution bottles.

Letter: Intravenous solution bottles.


Infrarenal dissection of the aorta.

Infrarenal dissection of the aorta. Three patients with infrarenal aortic dissection are described and the pathogenesis, investigation and treatment of this condition briefly discussed.


Editorial: Reading the journal.

Editorial: Reading the journal.


New Zealand Committee on Adverse Drug Reactions: Tenth Annual Report 1975.


Letter: Information for pathologists and doctors requested to obtain samples for forensic investigations.


Letter: Mass radiography and lung cancer.


Letter: Tetracyclines in children.

Letter: Tetracyclines in children.


Late recurrence following acute haematogenous osteomyelitis. The results of the treatment of 168 children with acute osteomyelitis in Auckland between 1951 and 1955 were reviewed with a particular interest in late recurrence. The early failure rate of 20 percent is comparable with other recent series. Follow-up of the 134 apparent cures revealed five late recurrences, an incidence of 3.0 percent but follow-up was incomplete (44 cases) and the late recurrence may be higher.


Letter: The proof of poison an open letter to pathologists.


Letter: Secretory otitis media.

Letter: Secretory otitis media.


Letter: The medical association of new zealand proceedings of council meeting held on wednesday, 10 september 1975.


The evaluation process.

The evaluation process.


Change in nursing education.

Change in nursing education.


On nursing standards.

On nursing standards.


Effects of smoking on health.

Effects of smoking on health.


Feline infectious peritonitis: a review.


Nuclear family alternatives.

Nuclear family alternatives.


The effects of copper supplementation on stock health and production. 3. The effect of parenteral copper on the milk yield characteristics of a dairy herd with hypocuprosis.


Hairy shaker disease: preliminary studies on the nature of the agent, and the induced serological response.


Critical test evaluation of micronized mebendazole against Anoplocephala perfoliata in the horse.


Letter: The brown dog tick (Rhipicephalus sanguineus) on an imported dog.


Letter: Capillaria infection in a pig.

Letter: Capillaria infection in a pig.


Physiological limits to performance.

Physiological limits to performance.


Down to earth.

Down to earth.


Electrocardiographic anomalies in the racehorse.


Training for running races.

Training for running races.


The training of guide dogs for the blind.


Some overseas developments in sheep and beef production.


Diseases of the vulva, vagina and cervix of the thoroughbred mare.


Canine hip dysplasia. 2: Control and treatment.


Blood sampling for inorganic phosphate analysis.


In vitro sensitivity of New Zealand strains of Mycoplasma ovipneumoniae to some antibiotics.


Studies on the pathogenicity of Cooperia curticei for sheep.


Congestive heart failure in broilers, resembling toxic heart degeneration and chick oedema disease.


Successful treatment of suspected thoracic nocardiosis in a dog.


Letter: Leptospirosis in the opossum (Trichosurus vulpecula).


Malignant hyperthermia in a crossbred Landrace-Large White pig.


Experimental Ostertagia infection of sheep: pathology following a single high dose of larvae.


Letter: Isolation of Leptospira hardjo from the opossum (Trichosurus vulpecula).


Acupuncture laws updated.

Acupuncture laws updated.


Hospital dentistry: an analysis and a proposal.


Outgoing president's address. The ADA, our greatest resource.


Letter: American Dentists for Foreign Service, Inc.


Public education. Orthodontic treatment for children.


Guidelines. On dental occlusion.

Guidelines. On dental occlusion.


Psychological aspects of the patient's history.


28th National Children's Dental Health Week. February 1-7, 1976.


In continuing education.

In continuing education.


New facility occupied at New Jersey Dental School.


Reflections of a new dean at Howard University.


Tufts focuses on total patient care.

Tufts focuses on total patient care.


Temple completes first phase of building program.


Letter: Contra compulsory continuing ed.


Editorial: Are you hep to PEP?

Editorial: Are you hep to PEP?


Editorial: Fee advertising--an FTC fallacy.


The changing profile of the temporomandibular joint dysfunction patient.


Attracting women to dentistry. A comprehensive recruitment program.


The compulsory continuing education debate. A pro advocate.


New programs initiated at Buffalo.

New programs initiated at Buffalo.


Columbia university exceeds goals. Improved financial picture.


NYU faces the challenge of change.

NYU faces the challenge of change.


Three classes admitted to SUNY at Stony Brook.


Advances at Fairleigh Dickinson University School of Dentistry.


Bicentennial activities at University of Pennsylvania.


University of Pittsburgh. Concerned with impact of third party programs.


Acute leukemia in advanced ovarian carcinoma after treatment with alkylating agents. Two cases of advanced ovarian carcinoma treated with chlorambucil and terminating in acute leukemia are presented and the literature reviewed. The first patient was diagnosed by laparotomy as having Stage III ovarian carcinoma, and total abdominal hysterectomy and bilateral salpingo-ophorectomy were performed. After 7 years and 2 months of chemotherapy, acute myeloblastic leukemia was diagnosed, and the patient expired 4 months later. At autopsy no residual ovarian tumor was found. The second patient had a right oophorectomy after the diagnosis of Stage III ovarian carcinoma had been made. After 5 years and 9 months of chemotherapy she developed acute myelomonocytic leukemia and expired 2 months later, with residual ovarian tumor present on autopsy. The benefits of surgical reexploration in occasional cases of good clinical remission after chemotherapy are discussed in view of potential carcinogenicity of cytostatic agents.


In vivo fluorine uptake in human enamel following treatment with a varnish containing sodium fluoride. Fluorine concentrations were determined in three successive enamel layers (approximately 10, 10 and 25 microns in width) of 21 pairs of contralateral teeth, by etching with perchloric acid. The F-concentrations in five untreated pairs of teeth were measured and compared (Group I). A decrease in the F-content from about 1100 ppm in the outer layer to 400 ppm at 40 microns from the enamel surface was found. The differences in F-concentrations between contralateral teeth extracted from the same mouth were small and not statistically significant. In five teeth (Group II) th F-uptake was determined one day after a single topical application of a varnish which contained 5% NaF (Duraphat), and compared with the corresponding control contralateral teeth. A significantly increased concentration of F was observed in all analysed enamel layers of the treated teeth: 3270 +/- 128 (1048 +/- 145), 1520 +/- 97 (596 +/- 61), 567 +/- 52 (296 +/- 14) ppm. Values within brackets denote concentrations in control teeth. In another five teeth (Group III) the fluorine concentration was determined one week after a single application of Duraphat. A significant increase in the F-concentrations in three enamel layers of the test-teeth was found as compared to the control-teeth: 1732 +/- 156 (884 +/- 101), 904 +/- 82 (464 +/- 79) and 524 +/- 88 (296 +/- 24) ppm F. The test-teeth in this group contained less fluorine in the outermost enamel than did the teeth in group II. The difference was significant for the outer two layers. Approximately the same concentration of fluorine was found in test-teeth analysed five weeks after treatment as observed at one week, using same varnish (Group IV). The respective values were: 1795 +/- 410 (907 +/- 216), 749 +/- 135 (369 +/- 90), 382 +/- 88 (166 +/- 40) ppm. The F-increase was significant for all enamel layers analysed.


Proton activation analysis studies on fluorine and nitrogen content of developing dental enamel. Proton activation analysis, using the reactions 19F(p, alpha gamma)16O and 15N(p, alpha gamma)12C, was employed to study the fluorine and nitrogen content of developing rat molar enamel at various stages of maturation. Four groups of rats were utilized: Group I -- injected intraperitoneally at 6 days of age with 20 mg F/kg b.w. as sodium fluoride solution and terminated at 30 minutes and 1, 5 and 9 days postinjection; Group II -- injected in a similar way at 7 days of age and terminated 30 minutes and 1, 4 and 8 days postinjection; Group III -- injected with 10 mg F/kg, at 6, 15 and 19 days of age and terminated 30 minutes later; Group IV -- control animals injected with distilled water at 6 and 15 days of age respectively and terminated 30 minutes later. Analysis reflected decreasing nitrogen content in the enamel as maturation proceeded. However, fluorine concentrations were highest in all groups at the earlier stages of enamel development.


Structural studies on polysaccharides synthetised from sucrose by soluble enzymes in human dental plaque material. Soluble enzymes in human dental plaque material were shown to synthetise a polysaccharide material when incubated with sucrose. The polysaccharide mixture was fractionated by gel chromatography and the major fraction (Mw congruent to 95,000) was characterised as a mixture of a alpha-(1 leads to 6)-linked glucan with branches linked alpha-(1 leads to 3) to the main chain and a beta-(2 leads to 6)-linked fructan with branches in the 1-position of the chain residues.


Characteristics of Streptococcus milleri and Streptococcus mitior from infected dental root canals. Morphological and physiological characteristics of 103 streptococcal isolates obtained from positive routine cultures of material from dental root canals at filling, were studied. The majority of the isolates were those which at a primary identification not fullfilled the criteria of enterococci, Strep. sanguis, Strep. mutans or Strep. salivarius. Only a few representative strains of the latter types were included in the study as a control of the method. The resemblance of the 103 isolates to 38 reference strains were assessed with numerical methods. The isolates formed 9 clusters with reference strains occurring in all but one. Of the isolates which it was intended to identify and characterize with numerical taxonomic analysis, all but one joined one of 3 clusters and were identified as Strep. milleri or Strep. mitior (mitis). The most useful cultural characteristics to dfferentiate the two species were growth on the sulphonamide containing MC-agar and 7.5% bile blood agar by Strep. milleri and production of hydrogen peroxide by Strep. mitior. The characteristics of the strains in the nine 80-phenons are given in Table 2. Other characteristics that appeared to be of interest for differentiating Strep. milleri from Strep. mitior and these two species from other viridans streptococci are underlined in Table 2. Strep. milleri seems not earlier to have been reported to occur in infected root canals. The occurrence of Strep. milleri is in agreement with the data given on serological groups found among streptococcal isolates from routine root canal cultures. Little is known about the occurrence and distribution of Strep. milleri in the human oral cavity, which therefore warrant further investigations.


Metastatic melanoma of the maxilla presenting as a gingival swelling. Malignant melanoma metastatic to the gingiva has been reported only once. We present a case in which the occurrence of melanoma in the gingiva followed extraction of a periapically "abscessed" tooth. Since the initial periapical mass may well have been a metastatic tumor, particularly in a patient undergoing therapy for disseminated malignant disease, the need for biopsy of such lesions is emphasized.


The effects of thermal and electrical injury on pulpal histamine levels. The present investigation was undertaken to determine possible quantitative changes in porcine pulpal histamine levels following thermal and electrical insult. Quantitative spectrophotofluorometric assays revealed a fourfold increase in pulpal histamine levels within 30 minutes of thermal injury. These findings suggest that histamine may play a role in the initial stages of pulpal inflammation. Electrical insult was found to have no significant effect on pulpal histamine contents 30 minutes after insult. The possible implications of these findings are discussed.


Cytogenetic and histochemical analysis of experimental oral carcinogenesis in the rat. The present investigation has shown that in chemical carcinogenesis progression of malignant epithelial changes in associated with an increased number of cells with chromosomal deviations. Each out of two oncogenic agents with different chemical characteristics had its own non-random pattern. There was usually a close relationship between such chromosomal changes and the simultaneous presence of morphological atypia (dysplasia) and metabolic atypia (aberrant G-6-P.DH activity) from moderate dysplasia and onwards during carcinogenesis. Changes in X-chromosomes, which i.a. in human code the synthesis of G-6-P.DH molecules, could perhaps explain and be reflected in deviating metabolic reactions in premalignant cells.


Radiographic interpretation of so-called developmental defect of mandible. Ten cases of so-called development defect were detected on panoramic radiograms. One of them was bilocular, two were round, three were ovoid, and four were half-ovoid. Eight were in men and two were in women. These cystlike lesions are sometimes misdiagnosed as epithelium-lined cysts or benign tumors, such as ameloblastoma. For the detection of this kind of defect, panoramic radiography is available, and the lesion is differentiated from many cysts and tumors in the jaws by posteroanterior projection and occlusal films. From the published literature, some tendencies of age distribution and sex incidence were reviewed.


Change in working length following instrumentation of molar canals. A study was undertaken to determine the reduction in working length following instrumentation of molar canals. A sample of forty maxillary and forty mandibular extracted teeth was used. The canals were measured before and after instrumentation. The greatest changes were observed in the mesiobuccal canal of the maxillary molars, which showed a mean reduction of 0.35 mm. with a range of 0.8 mm. The smallest changes were observed in the palatal canal of the maxillary molars and the distal canal of the mandibular molars. These canals showed a mean change of less than 0.1 mm. None of the changes were statistically significant.


Warthin's tumor. Report of a case and survey of 205 salivary neoplasms. A case of Warthin's tumor with an unusual sialographic appearance is reported. The extensive pooling of the contrast media within the tumor was probably the result of communication of the cystic spaces of the tumor with the ductal system of the parotid gland. This case stimulated a re-examination of the incidence of this tumor, with a study of 205 major salivary gland tumors from pathology reports in the files of Hartford Hospital which is affiliated with the University of Connecticut Health Center in Farmington, Connecticut.


The retrognathic mandible--surgical correction. The preceding case reports demonstrate the excellent results available to the patient with a retrognathic mandible. Etiology, adverse effects, and the modalities used in evaluation of the underdeveloped mandible have been discussed. The age at which surgical intervention is undertaken needs additional input by clinicians. Several surgical procedures have been and are employed to advance the mandible. The C osteotomy is recommended since the final result has been excellent and consistent. The surgeon has constant surgical control and vision. The advanced portion of the mandible can be firmly held by intraosseous wires. There is minimak disturbance of muscle position and the inferior alveolar nerve. We have not encountered unusual loss of blood, immediate postoperative problems with the airway, infection, or unfavorable relapse. A postoperative regimen that has been found rewarding is discussed. We have come to the conclusion that most patients can tolerate lengthy surgical procedures with few adverse side effects. Our colleagues in anesthesia and nursing provide superb operative and postoperative care. When the preoperative work-up indicates that more than one procedure is indicated, we recommend that the total surgical treatment plan be carried through at one operation, although occasionally this approach may be contraindicated. We should strive for perfection and can fall short of this goal when a patient will not return for additional surgical procedures which could have been accomplished during the first operation. Although good results have been experienced with both the C osteotomy and the sagittal split osteotomy, we believe that the C osteotomy is a superior procedure. However, this does not imply that the sagittal split osteotomy should not be a part of the armamentarium of the oral surgeon. In conclusion, the C osteotomy, the sagittal split osteotomy, genioplasty, and additional procedures--such as a mandibular alveolar osteotomy to intrude supraerupted teeth--when indicated, can provide very favorable results in cases of retrognathia or micrognathia of the mandible.


Three cysts in close proximity.

Three cysts in close proximity.


Potential of elastin and collagen as initiators of in vivo calcification. The osseous repair response of the guinea pig to purified bovine elastin from ligamentum nuchae and decalcified rat femur collagen was studied by implantation of these materials into an extraction socket. A nylon mesh tube was used to carry the respective implant materials to place, and in one group of animals only the nylon tube was implanted, thereby serving as a control for the study. Neither the collagen or elastin matrix appeared to elicit an immune rejection response from the host animal. Histologic and quantitative results indicated that collagen implants accelerated the osseous repair of the extraction socket. Elastin implants, which characteristically resulted in ossicle formation, did not appear to accelerate healing, but the results were quantitatively similar to those in the experimental control animals.


Nomalike lesion in a patient with chronic lymphocytic leukemia. Review of the literature and report of a case. A case in which a nomalike lesion occurred in a patient being treated for chronic lymphocytic leukemia has been reported. Differential diagnosis of noma from other oral gangrenous processes has been described. The pathophysiology of systemic disease and blood dyscrasias contributing to the development of the lesion has been discussed with reference to management and treatment. A review of the literature is included.


Letter: Denture-related candidiasis.

Letter: Denture-related candidiasis.


Florid osseous dysplasia. A clinical-pathologic study of thirty-four cases. Thirty-four patients with florid osseous dysplasia were studied. The majority were asymptomatic Negro women: Seventeen biopsy-proven simple bone cysts were found in affected quadrants of fourteen patients. Radiographs displayed a spectrum of sclerotic and ground-glass opacities limited to alveolar processes but not to root apices. Biopsy material was studied in all cases, and biochemical analyses of serum and cyst fluid were performed on some patients. Test results and skeletal radiographs indicate that the disease is limited to the jaws. Patients have remained asymptomatic with little alteration of radiographic patterns. Three cysts failed to heal following treatment, others filled with radiographically abnormal tissue. Chronic osteomyelitis may infrequently complicate the disease. These cases appear to represent the most exuberant manifestation of this reactive fibro-osseous jaw disease.


A clinical study of cysts arising from mucosa of the maxillary sinus. Panorex radiographs taken during the past 5 years at the University of Kentucky College of Dentistry were reviewed for evidence of mucosal cysts of the maxillary sinus. Thirteen patients with this lesion were recalled for re-evaluation of their status. Ten of the patients had symptoms that could be related to the involved sinus. These included stuffiness, fullness, postnasal drip, gushing of yellow fluid from the nose, and headache. Radiographic examination revealed that three of the cysts had increased is size, three had decreased in size, three had not changed in size, and two had disappeared; no evaluation could be made on two. On the basis of radiographic, transillumination, history, and clinical findings, the nine cysts that could be evaluated were diagnosed as being of the nonsecretory type of mucosal cyst. We recommended periodic radiographic examination for this type of lesion. Surgical intervention is necessary only if destruction of surrounding bone has occurred or recurrence of disturbing symptoms is reported.


The effect of radiation-induced xerostomia on saliva and serum lysozyme and immunoglobulin levels. Saliva and serum lysozyme, immunoglobulin, albumin, and total protein levels were monitored in thirty patients with cancer of the head or neck before, during, and after radiotherapy and compared with those of a group of non-irradiated noncancer control subjects. The mean volume-based saliva lysozyme and total protein concentrations were significantly higher in the cancer patients before radiotherapy than in the control group. During radiotherapy, the mean volume-based concentrations of all protein components assayed increased as the saliva flow rate decreased. Protein-based ratios of saliva albumin, IgG, and lysozyme and the ratio of IgG/IgA increased as the xerostomia intensified. Ratios of saliva total protein and IgA to flow rate paralleled the flow rate decrease. Such increased concentrations in saliva immunoproteins were offset, however, by a greater than 93 per cent reduction in total saliva output. This reduced saliva output, therefore, resulted in an immunoprotein deficit. There were no significant differences between the mean serum lysozyme levels of the cancer and control groups at any point of comparison. The mean serum immunoglobulin concentrations in the cancer patients before radiotherapy were significantly higher than those in the control group. During radiotherapy, there was a decrease in the mean serum total protein, albumin, and immunoglobulin levels which reverted toward the pretreatment values during the postirradiation period.


Bilateral eosinophilic granuloma of the mandible. A case of extensive bilateral eosinophilic granuloma of the mandible has been reported. The pertinent clinical features have been emphasized and difficulties in diagnosis have been discussed. The case highlights the problem that faces the surgeon and pathologist when there is a superimposed chronic osteomyelitis. If the lesion had been limited to the left side of the mandible and if the possibility of eosinophilic granuloma had not been raised on histologic grounds at the time of original exploration, then a correct diagnosis might not have been reached.


Incidence of hypothyroidism after radioiodine treatment of hyperthyroidism: a report of the radioiodine therapy follow-up study.


Perfusion chemotherapy of osteosarcoma. A clinical study on 75 cases.


"Cervical hernias of the lung in congenital biliary atresia".


Extremity perfusion chemotherapy. Past, present and future.


Estimates of stratospheric pollution by an analytic model. With suitable choices of the height profile of eddy diffusion coefficient, the vertical flow of an inert tracer is given by an analytic solution. Odd nitrogen, or NOX, from aircraft exhausts can be regarded as such a tracer, and the amount in the stratosphere resulting from a source of a given strength can be immediately calculated. The resulting destruction of ozone is then estimated with the help of a formula obtained from earlier work.


Energy transfer between terbium (III) and cobalt (II) in thermolysin: a new class of metal--metal distance probes. The visible fluorescence of terbium(III) when bound to a calcium binding site of thermolysin is greatly enhanced with an excitation maximum at 280 nm but substitution of cobalt(II) for zinc at the active site decreases the intensity by 89.5%. Treatment with N-bromosuccinimide quenches enzyme tryptophan and Tb(III) fluorescence to a similar extent and suggests the operation of tryptophan vector Tb(III) vector Co(II) energy relay system in the enzyme. Dipoledipole radiationless energy transfer between the Tb(III) donor and the Co(II) acceptor can account for this quenching. The inherent characteristics of the metal pair limits the value of the orientation factor, K2, of the Förster equation, thereby reducing uncertainties in distance measurements by energy transfer compared with other systems. A quantum yield of 0.51 yields a value of R0, the distance for 50% energy transfer, of 19.6 A, and a distance, R, between Tb(III) and Co(II) of 13.7 A, a value identical to that measured for the distance between the active site zinc atom and calcium atom number 1 by x-ray analysis in native thermolysin crystals. The limits of confidence of this measurement are discussed. Energy transfer between two different metal atom sites of a protein provides a new class of probes to measure intramolecular distances of biological macromolecules in solution.


Isolation and characterization of two acidic proteins of 60s ribosomes from Artemia salina cysts. 60S ribosomes from encysted gastrulae of the brine shrimp Artemia salina contain two acidic proteins, which are homologous to the Escherichia coli proteins L7 and L12. The proteins were purified and characterized with respect to molecular weight, amino-acid composition, peptide maps, and their functional requirement in the elongation factor dependent binding of aminoacyl transfer RNA to the ribosome.


Lambda repressor turns off transcription of its own gene. We report transcription in vitro of the lambda repressor gene, cI, using specific restriction endonuclease fragments as templates. This transcription is repressed by lambda repressor. Moreover, we report the sequence change caused by a cI promoter mutation. This change is located between two repressor binding sites in the rightward operator (OR). Transcription studies using mutant templates indicate that repressor bound to two sites in OR regulates transcription of gene tof, and repressor bound to the remaining site(s) controls transcription of cI.


X-ray fiber diffraction evidence for neighbor exclusion binding of a platinum metallointercalation reagent to DNA. Good quality x-ray diffraction patterns have been obtained of polycrystalline fibers containing 2-hydroxyethanethiolato(2,2'2"-terpyridine)platinum(II) bound to calf thymus DNA by intercalation. The photographs strongly support the neighbor exclusion binding model in which electron-dense platinum atoms are regularly distributed at 10.2 A intervals, every other interbase pair site.


Inhibition of citrate synthase by oleoyl-CoA: a regulatory phenomenon. Fatty acyl-CoAs are good detergents (dritical micelle concentrations = 3-4 muM) and can inhibit a number of enzymes, including some involved in fatty acid biosynthesis. The regulatory significance of fatty acyl-CoAs as negative effectors has been questioned largely because of the difficulties in distinguishing possible nonspecific detergent effects from more specific regulatory interactions with these enzymes. A new analogue of oleoyl-CoA, oleoyl-(1, N6-etheno)-CoA, is a better detergent (critical micelle concentration = 3.2 muM) than oleoyl-CoA (critical micelle concentration = 4.7 muM). This new analogue is not as good (by an order of magnitude) an inhibitor of citrate synthase [citrate oxaloacetatelyase (pro-3S-CH2-COO-vectoracetyl-CoA); EC 4.1.3.7] nor is it bound as well oleoyl-CoA. Since the only difference between these two compounds is substitution of 1,N6-ethenoadenine for the adenine of CoA, the difference in inhibition and binding implies a specific interaction between the adenine moiety of oleoyl-CoA and citrate synthase. Moreover, since oleoyl-(1,N6-etheno)CoA is a better detergent than oleoyl-CoA, the detergency of oleoyl-CoA is not the sole cause of the fatty acyl-CoA inhibition of citrate synthase. These results support a physiological role for oleoyl-CoA as a negative effector for citrate synthase. An analogous physiological role for fatty acyl-CoA as negative effectors for other enzymes seems reasonable.


Reconstruction of bacteriophage T4 DNA replication apparatus from purified components: rolling circle replication following de novo chain initiation on a single-stranded circular DNA template. The protein products of T4 bacteriophage genes 41, 43, 45, 44, and 62 have been purified to near homogeneity using an assay which measures their stimulation of DNA synthesis in a crude lysate of Escherichia coli cells in fected by an appropriate mutant phage. When all of these proteins and T4 gene 32 protein are incubated in the presence of deoxyribonucleoside and ribonucleoside triphosphates, extensive DNA synthesis occurs on both single and double-stranded DNA templates. Analysis of this in vitro system reveals most of the features attributed to in vivo DNA replication: (1) De novo DNA chain initiation is found on a single-stranded DNA template only if ribonucleoside triphosphates are present (as expected for RNA priming of Okazaki pieces on the "lagging" strand of a replication fork). (2) With single-stranded circular DNA as template, synthesis continues for many doublings. The products after extensive synthesis resemble a rolling circle as visualized in the electron microscope, with discontinuous "lagging" strand synthesis generating a long, unbranched double-stranded tail. The fact that all six mutationally identified T4 replication gene products are required for these syntheses suggests the existence of a large multienzyme complex, constituting the T4 replication apparatus.


Statistical theory of chromatography: new outlooks for affinity chromatography. We have developed further the statistical approach to chromatography initiated by Giddings and Eyring, and applied it to affinity chromatography. By means of a convenient expression of moments the convergence towards the Laplace-Gauss distribution has been established. The Gaussian character is not preserved if other causes of dispersion are taken into account, but expressions of moments can be obtained in a generalized form. A simple procedure is deduced for expressing the fundamental constants of the model in terms of purely experimental quantities. Thus, affinity chromatography can be used to determine rate constants of association and dissociation in a range considered as the domain of the stopped-flow methods.


NH---S hydrogen bonds in Peptococcus aerogenes ferredoxin, Clostridium pasteurianum rubredoxin, and Chromatium high potential iron protein. Results from refinement of the crystal structures of P. aerogenes ferredoxin and C. pasteurianum rubredoxin determined by x-ray diffraction show that there are 15-18 NH---S bonds in the former and six in the latter with lengths in the range 3.1-3.9 A. Earlier tritium exchange experiments are consistent with the presence of these hydrogen bonds in the ferredoxin structure and show that more peptide hydrogen atoms are available for exchange in apoferredoxin than in intact ferredoxin. Four types of NH---S bonds are observed and two of these are geometrically similar to the two types of 3(10) NH---O bonds. The existence of more NH---S bonds in ferredoxin than in high potential iron protein suggests why the -2 form of the Fe4S4 cluster is preferred in ferredoxin over the -1 form found in high potential iron protein. From comparison of Cys-X-Y-Cys sequences in rubredoxin, ferredoxin, and high potential iron protein we suggest that two Cys-X-Y-Cys-Z sequences, where Z may have conformation angles similar to glycine, are required to make a one-iron cluster, no more than one Cys-X-Y-Cys-Z-Gly sequence is required to form a Fe2S2 ferredoxin, and a Cys-X-Y-Cys-Gly sequence where Y has a conformation such that the cysteines bond to different iron atoms is necessary to form the tetrameric cluster.


Structural requirements for time-dependent inhibition of prostaglandin biosynthesis by anti-inflammatory drugs. Several anti-inflammatory drugs have been examined for their ability to cause a time-dependent destruction of the fatty acid oxygenase that produces prostaglandins. All of the time-dependent inhibitors contained carboxylic acid moieties, and in addition all but one of the drugs contained a halogen atom. Structural analogs (of the time-dependent inhibitors) lacking halogen atoms were unable to cause a time-dependent destruction of the enzyme. The time-dependent property of an inhibitor was totally eliminated after methylation of the carboxylate group. Methylation did not, however, alter the ability of the inhibitors to competitively inhibit the oxygenase. Thus, the reversible binding of the agents at the active site was not appreciably dependent upon the free carboxyl group, whereas the subsequent irreversible process was.


Spike-forming model of the neural membrane: computer simulation of some perfused axon experiments. This paper is an attempt to account for the action potential spikes observed when the normal axoplasm of a squid giant neuron is replaced by a postassium-free, sodium-rich fluid, and the axon is immersed in a potassiumand sodium-free, calcium-rich bath. For this purpose a recently described model of the neural membrane [Wooldridge, D. E. (1975) Proc. Nat. Acad. Sci. USA 72, 3468-3471] is extended. Allowances are made for the flow of Ca++, Cl-, and Na+ ions through some of the membrane pore configurations, as well as for some electron conductance, all of amounts too small to be significant in the normal neuron. It is also postulated that the nature of the perfusing fluid affects the rates of some of the reactions that change the convertible gates from one configuration to another, as well as the ionic permeabilities of the resulting configurations. The result of the modifications is a single membrane model that accounts for the 3-sec, 15 muA/cm2 action potential spikes of the perfused axon as well as for the 0.5-msec, 1 mA/cm2 spikes of the normal neuron.


Cytoplasmic and nuclear binding components for 1alpha25-dihydroxyvitamin D3 in chick parathyroid glands. Specific binding of 1 alpha,25-dihydroxyvitamin D3 [1alpha,25-(OH)2D3] to macromolecular components in the cytoplasm and nucleus is demonstrated in parathyroid glands of vitamin-D-deficient chicks. The interaction of 1alpha,25-(OH)2D3 with the cytoplasmic binding component is of high affinity (Kd = 3.2 X 10(-10) M) and high specificity [1alpha,25-(OH)2D3 greater than 25-hydroxyvitamin D3 greater than 1alpha-hydroxyvitamin D3 greater than vitamin D3 in competing with radioactive 1alpha,25-(OH)2D3]. Both cytoplasmic and nuclear hormone-macromolecular complexes sediment at 3.1 S in 0.3 M KC1-sucrose gradients, and agarose gel filtration of the components indicates an apparent molecular weight of 58,000. The 3.1S binding molecules are not observed in adrenal gland, testes, liver, or kidney, but similar receptors for 1alpha,25-(OH)2D3 have been found previously in intestine. Macromolecular species with a high affinity and preference for 25-hydroxyvitamin D3 [25-(OH)D3] are also identified in parathyroid cytosol and differ from the parathyroid 1alpha,25-(OH)2D3-binding component in that: (1) they sediment at 6 S in 0.3 M KC1-sucrose gradients, (2) they are observed in all tissues examined, (3) they have a higher affinity for 25-(OH)D3 than 1alpha,25-(OH)2d3, and (4) they are not found in the nucleus of the parathyroid glands, in vitro. The discovery of unique 1alpha,25-(OH)2D3-binding components in the parathyroid glands is consistent with the sterol hormone's action at this endocrin site and possible involvement in the regulation of parathyroid hormone synthesis and secretion.


Search for nucleic acid sequences complementary to a murine oncornaviral genome in poly(A)-rich RNA of human leukemic cells. The presence of viral-like sequences in the RNA of various types of leukemic cells was investigated by hybridizing cellular poly(A)-containing RNA with cDNA synthesized in an endogenous system of purified Moloney murine sarcoma virus [M-MSV-(MLV)]. Poly(A)-RNA-cDNA hybrids were detected by assaying their resistance to S1 nuclease. Hybrids were found in 22 out of the 46 leukemias that were tested. None of the controls, including material obtained from buffy coats, bone marrow cells, and a continuous human cell line, was positive. Positive cases were found in all the different categories of leukemias with the exception of chronic myelogenous leukemias. There was no definite corelation between the category of leukemia and positivity. A few cases contained a very high proportion of poly(A)-RNA-cDNA hybrid.


Interferon activity produced by translation of human interferon messenger RNA in cell-free ribosomal systems and in Xenopus oöcytes. Translation of messenger RNA isolated from poly(rI)-poly(rC)-induced human fibroblasts in cell-free ribosomal systems and in Xenopus oocytes resulted in the production of biologically active proteins that had the properties of human fibroblast interferon. The translation in the oocytes was much more efficient, giving approximately 500 times higher titers of interferon activity than the cell-free systems. A control messenger RNA isolated from noninduced human fibroblasts, did not code for interferon synthesis in these systems. Both messenger RNA preparations stimulated [3H]amino-acid incorporation into trichloroacetic acid-insoluble material. The radioactive products and their immunoprecipitates were electrophoresed on polyacrylamide gels under denaturing conditions. The products resulting from the translation of the control (uninduced) messenger RNA in oocytes contained a major protein of approximately 45,000 molecular weight. The messenger RNA isolated from poly(rI)-poly(rC)-induced cells stimulated the synthesis of an additional 25,000 molecular weight protein that electrophoresed in the same position as human fibroblast interferon. These results suggest that human fibroblast interferon was synthesized by the translation of its messenger RNA in Xenopus oocytes and in cell-free ribosomal systems.


Effect of rotation on the diffusion-controlled rate of ligand-protein association. The rate of binding a fairly large ligand molecule to a protein is reduced below the usual diffusion-controlled rate by the requirement of a certain rotational orientation. A simple, approximate treatment of this effect is given for special cases of spherical and ellipsoidal ligands. As the center of an ellipsoidal ligand approaches a protein surface, there is an effective repulsive potential between ligand and surface owning to restricted rotation of the ligand. The frequency factor kT/h of the Eyring rate theory is replaced in these reactions involving diffusion in solution by D/Rlambda, where D = diffusion coefficient of ligand, lambda = thermal deBroglie wavelength of ligand, and R = "capture" distance around the binding site on the protein.


Procollagen: biological scission of amino and carboxyl extension peptides. Procollagen, the triple-stranded precursor of chick embryo skull bone collagen, contains two pro alpha1 and one pro alpha2 chains. We find that each of these is a collagen chain with both an NH2-terminal and a COOH-terminal extension peptide. The NH2-peptide of pro alpha1 contains cysteine and differs from the NH2-peptide of pro alpha2. The three NH2-peptides are cut off, giving a disulfide-linked intermediate, named altered procollagen; then the disulfide-linked COOH-peptides, which contain cysteine and tryptophan, are cut off, leaving collagen. Procollagen, altered procollagen, and COOH-peptide were isolated. Collagenase digestion of procollagen gave both NH2- and COOH-peptides, while altered procollagen gave only COOH-peptides. The following results of sequential, in vitro labeling at 37 degrees and of specific cleavage of procollagen proved the structure: [(NH2-peptide)-collagen-(COOH-peptide)]3 with interstrand S-S links between only the COOH-peptides. (i) The COOH-peptides of pro alpha chains were labeled with [3H]proline before the remainders of the chains; (ii) [35S]cysteine appeared in the COOH-peptides of completed covalent molecules 5 min earlier than in the NH2-peptides; (iii) tadpole tail collagenase, which cuts native collagen into triple-stranded 3/4 pieces containing the NH2 termini and 1/4 pieces containing the COOH ends, cuts procollagen into 3/4 pieces with NH2-peptides attached and 1/4 pieces attached to the disulfide-linked COOH-peptides. The COOH-peptides of pro alpha 1 and pro alpha2 were labeled in a 2:1 ratio at 4 min, indicating simultaneous translation of pro alpha1 and pro alpha2.


Three-dimensional structure of herring sperm protamine Y-I with the aid of dark field electron microscopy. High resolution electron micrographs of herring sperm protamine (clupeine) Y-I provide sufficient detail to constrain the folding of the known amino-acid sequence of the protein into a unique three-dimensional configuration. The structure consists of a loose helix of turns of various sizes held together at one edge, spread apart along the other. This form appears to represent the shape of several fish protamines.


Infectious viral DNA of murine leukemia virus. A fraction of the unintegrated viral DNA that appears early after infection of mouse cells by Moloney leukemia virus is infectious. The infectivity could be deomonstrated by an XC plaque assay of the cells exposed to DNA co-precipitated with calcium phosphate. The number of plaques deriving from closed-circular, supercoiled DNA was proportional to the concentration of added DNA, indicating that a single DNA molecule of about 5.5 X 10(6) daltons carries all the viral information. Nonsupercoiled viral DNA is also infectious; these molecules appear to be largely double-stranded and 5 to 6 X 10(6) dalthons in mass.


Analogue solution for electrical capacity of membrane covered square cylinders in square array at high concentration. Analytical solutions of Laplace equations have given the electrical characteristics of membranes and interiors of spherical, ellipsoidal, and cylindrical cells in suspensions and tissues from impedance measurements, but the underlying assumptions may be invalid above 50% volume concentrations. However, resistance measurements on several nonconducting, close-packing forms in two and three dimensions closely predicted volume concentrations up to 100% by equations derived from Maxwell and Rayleigh. Calculations of membrane capacities of cells in suspensions and tissues from extensions of theory, as developed by Fricke and by Cole, have been useful but of unknown validity at high concentrations. A resistor analogue has been used to solve the finite difference approximation to the Laplace equation for the resistance and capacity of a square array of square cylindrical cells with surface capacity. An 11 x 11 array of resistors, simulating a quarter of the unit structure, was separated into intra- and extra-cellular regions by rows of capacitors corresponding to surface membrane areas from 3 x 3 to 11 x 11 or 7.5% to 100%. The extended Rayleigh equation predicted the cell concentrations and membrane capacities to within a few percent from boundary resistance and capacity measurements at low frequencies. This single example suggests that analytical solutions for other, similar two- and three-dimensional problems may be approximated up to near 100% concentrations and that there may be analytical justifications for such analogue solutions of Laplace equations.


Localization of cytoplasmic-membrane-associated DNA in human chromosomes. In situ hybridization was used to localize the sites of the repeated sequences of cytoplasmic-membrane-associated DNA (cmDNA) in human chromosomes. cmDNA was mainly present in the heterochromatic regions of chromosomes 9. Although cmDNA has buoyant densities in neutral and alkaline CsCl gradients similar to those of human satellite C DNA, which also is localized in the heterochromatic region of chromosomes 9, cmDNA was not homologous to satellite C DNA as determined by DNA-complementary RNA hybridization. These results are in agreement with our previous studies, which indicated that cmDNA is a unique species of human DNA.


Differences among myosins synthesized in non-myogenic cells, presumptive myoblasts, and myoblasts. Myosins synthesized in non-myogenic cells and replicating presumptive myoblasts differ from those synthesized in postmitotic mononucleated myoblasts and myotubes. Myoblasts and myotubes synthesize the definitive light chains, MLC1 and MLC2. These light chains display different molecular weights in sodium dodecyl sulfate-polyacrylamide gels from the fibroblast light chains FLC1 and FLC2 synthesized in non-myogenic cells and presumptive myoblasts. There are immunological differences between the myosin heavy chains synthesized in myoblasts and myotubes and those synthesized in non-myogenic cells and presumptive myoblasts. Fluorescein-labeled antibodies against skeletal light meromyosin are bound only along the lateral edges of emerging and definitive A-bands. This antibody to light meromyosin is not bound to the outside of, or the microfilaments subtending, the plasma membrane in non-myogenic cells or in myoblasts or in myotubes. These findings suggest that: (1) non-myogenic cells and replicating presumptive myoblasts synthesize similar myosin heavy and light chains; (2) replicating presumptive myoblasts synthesize a different set of myosins from those synthesized by their postmitotic daughters, the myoblasts; (3) the myosins associated with the plasma membranes of non-myogenic and myogenic cells are products of structural genes distinct from those coding for the myosins for skeletal myofibrils.


Membrane-microtubule interactions: concanavalin A capping induced redistribution of cytoplasmic microtubules and colchicine binding proteins. The relationship between microtubules and concanavalin A surface receptors during concanavalin A capping in primary cultures of rabbit ovarian granulosa cells was examined by electron microscopic and fluorescence labeling techniques. Cells treated with concanavalin A and hemocyanin at 4 degree or 37 degree and then incubated at 37 degree for 1 hr formed large juxtanuclear caps that were observed with shadow cast replicas of the cell surface. Thin section analysis of capped cells revealed an abundance of microtubules immediately beneath the cap which were arranged approximately perpendicular to the plane of the membrane. The capping process was unaffected by the antimicrotubule agents colchicine or vinblastine. Further, vinblastine treatment of capped calls resulted in the formation of numerous paracrystals that were confined to the cytoplasm underlying the capped region of the membrane; uncapped cells displayed paracrystals that were randomly dispersed in the cytoplasm. Exposure of fixed cells to fluorescein thiocarbamyl colchicine, which localizes colchicine binding proteins, revealed an intensely fluorescent region that corresponded to the cap; this staining pattern was absent in uncapped cells. These findings indicate that concanavalin A mediated capping modifies the cytoplasmic disposition of microtubules and colchicine binding proteins. Further, it is suggested that the capped region of the plasma membrane is a preferred site of microtubule polymerization.


Homology in amino-terminal sequence of precursors to pancreatic secretory proteins. Sequence determination of up to 24 amino-terminal residues of several putative precursors for dog pancreas secretory proteins, synthesized in vitro by translation of their mRNA's in the presence of radioactively labeled amino acids, revealed extensive sequence homology in the 16 amino-terminal residues. It is suggested that this common sequence constitutes a metabolically short-lived peptide extension which precedes the amino-terminal sequences of all pancreatic secretory proteins and that it functions in the transfer of these proteins across the microsomal membrane. This sequence was found to contain an unusually large percentage of hydrophobic residues.


Snythesis and differentiation of plasma proteins in cultured embryonic chicken liver cells: a system for study of regulation of protein synthesis. A new system is described for studying the control of protein synthesis. In a monolayer culture of chick embryo liver cells, plasma proteins are synthesized for three days at in vivo rates. The plasma proteins are secreted into the culture medium and without concentration are detected there simply and sensitively by a modified Laurell electronimmunoassay. Secretion of the newly synthesized plasma proteins occurs within 30 min of their synthesis. Thus, rates of synthesis of the plasma proteins can be followed readily from rates of their accumulation in the culture medium. This system has the following advantages for the study of protein synthesis: cells do not have to be disrupted for the assay; the cell population can be followed over several days; it is not necessary to label the proteins radioactively; and turnover of plasma proteins is negligible and need not be taken into account. The usefulness of the system is illustrated by a number of findings. The spectrum of plasma proteins synthesized in culture changed qualitatively and quantitatively. Albumin synthesis steadily decreased with culture time and stopped at the third day, whereas the synthesis of some new plasma proteins ("adult") was induced. These qualitative changes suggest differential gene expression in culture and a special control of albumin synthesis in vivo, different from the synthesis of the other plasma proteins. Quantitative changes in the rates of synthesis of specific plasma proteins suggest a competition among their messenger RNAs for components of the translational machinery. Insulin has a differential effect on the synthesis of specific plasma proteins at concentrations within the physiological range of the hormone.